enum TypeLink{
	ADDLEFT,
	ADDRIGHT,
	QUESTIONRIGHT,
	QUESTIONLEFT,
	REMOVE,
	INVALID
}
final class OperatorSymbol{
	public static final String ADDLEFT_OPERATOR = "->";
	public static final String ADDRIGHT_OPERATOR = "<-";
	public static final String QUESTIONLEFT_OPERATOR = "=>";
	public static final String QUESTIONRIGHT_OPERATOR = "<=";
	public static final String REMOVE_OPERATOR = "-";
	
	public static final String LINK_FINALOPERATOR = ".";
	public static final String QUESTION_FINALOPERATOR = "?";
}